The document provides a comprehensive guide on rewinding brushless motors, specifically using a delta wound dynam e-razor 450 model. It details the necessary steps for disassembly, stator insulation, winding procedures, and motor termination, emphasizing the importance of avoiding stator shorts during the process. The tutorial offers specific tips for choosing wire types, counting turns, and marking windings while ensuring proper insulation and connections for optimal motor performance.

1. Rewinding Brushless
Motors

2. Introduction
If you fly brushless you've probably cooked a motor or two. You also probably know
there are many different types of motors. Similar motors when wound differently perform very
differently. Whether you've burned the motor up, or just want to alter performance, rewinding
is a cheap solution for a patient modeller.
Rewinding brushless motors WYE or Delta
For this tutorial, I will be using Dynam E-Razor 450 Brushless Motor
60P-DYM-0011 (2750Kv). It is a Delta wound 8T (It means 8 turns) quad wind. The winding
pattern described in this tutorial (called an ABC wind - ABCABCABC as you go around the
stator) works for any brushless motor with 9 stator teeth and 6 magnets.
Fig.2 One Coil of Motor is Completely Burned
Definition of terms
1. Stator- The metal thing that holds the wire.
2. Rotor - The rotating part of the motor. This is the can on an out runner.

3. 3. Armature - houses one winding. Each motor has a number of armatures divisible by 3.
9 and 12 are common.
4. Turns - The number of times a wire is wound around each armature
5. Delta - Most common commercial termination. Has three leads and no neutral point.
Spins 1.7 times faster than a WYE termination.
6. WYE - Less common in commercial motors. More efficient in some cases. Has 1.7
times more torque than Delta
Knowing our motor
First, obviously you'll need to remove the old wires from the motor. Be sure to count
the number of turns around the armatures as this will give you an idea of how to rewind the
motor. The direction is not particularly important at this point.
You will also want to note whether it is Delta or Wye terminated. A Wye terminated
motor will have three wires going to a central point called the neutral, which is not connected
directly to a motor lead. A delta has no such connection, just three motor wires. Often the
neutral point one WYE has a piece of heat shrink over it to keep it from shorting to the stator.
Our motor is Delta Connected.
Fig. Removing old coil

4. Starting the rebuild
Before you do anything, I highly recommend insulating the stator. Take it from the king
of stator shorts, a stator short can easily destroy your speed control. I cannot stress enough how
much easier your rewind will be if you do this.
Most stators will be already insulated, but if you cooked your motor as well as I do that
coating is toast, in which case you'll need to reinsulate it. Start by using a small hobby file to
smooth all the rough corners on your stator. I used Black Rubber Paint.
Insulating Stator
 Deep stator in black paint and take off.
 Wait till paint set off.
 This is procedure is optional.
 If you burned the motor then its mandatory.
 If you want to change motor specification or your motor didn’t cooked then it is optional
Fig. Insulated Stator

5. Rewinding
 Ok, now to rewind. First you must choose the number of turns you want. My motor was
8 turns, and I liked it, so I'm going to rewind it with 8 as well.
 Here 8 Turns means, 8 strands of enamel coted copper wire are connected in parallel
which is wound on stator pole 8 times.
 Here 36 AWG copper wire is used.
 Rule of Thumb - less turns is a hotter motor and will yield a higher kv and current draw.
Go too low on this, however and the motor may not run as the speed control may not
detect the motor's position.
 You'll also have to choose whether you want a Delta or WYE termination.
 We are using delta connection as it was factory default.
Getting winding Pattern
Now you need the winding pattern. This motor is an 9N6P (9 stator pole, 6 magnet).
Therefore the winding pattern is ABCABCABC (each wire is wound every third tooth). This
winding pattern will not work with the very common 12N14P motor.
So before you start winding, count your magnets and stator poles and determine the winding
pattern from the list below. Lower case letters indicate winding that tooth in the reverse
direction.
9N6P-ABCABCABC
9N12P - ABCABCABC
9N8P (very rare) - AaABbBCcC
12N14P - AabBCcaABbcC <or> AaACBbBACcCB (I find this winding easier)

6. Winding Design
As we are planning on terminating Wye, mark the ending terminal of the wire. We'll need to
join the ending terminals of all three phases when it comes time to terminate the motor as
shown in following.
Start winding
 Now you can start winding.
 I used New-b wire (36 AVG) from nearby winding shop.
 It has extra insulation to prevent shorts. I chose three strands of 36 gauge wire. So it
will be an 8 turn of 8 wire bundle wind.
 Start winding with any pole you like. Go only in one direction (I went clockwise). Once
you complete the number of turns you decided on earlier, skip two poles and continue
winding the next. Repeat this process until one third of the poles are wired. It should
look like the picture below when you are done.
 Here third winding is to be done.
 Now before you begin with your next set of armatures, check for stator shorts with an
ohm meter (multi tester). The resistance between the wire and the metal of the stator
should be infinite (i.e. not continuity).

7.  If you don't get a short, good job. Move on to the next set of armatures. If you have a
short, unwind that entire phase get a new wire and start over.
 Side note: When winding, do not tug on the wires too hard. 1-2 lbs is plenty. Winding
too tight will result in a shorted winding to the stator. If you find that your wires are not
snug against your stator you can use a non-metallic object such as a broken prop, flat
carbon rod, or my favourite, a credit card to slide between the stator poles.
 Do tag the start and end of winding.
 Here start tag is S1 and end of 1st
winding is E1 as seen in pic on next slide.
Fig. tagging Motor terminals and checking motor winding
Ready for another set?
 Ready for another set? Start with a new wire on any other pole and repeat the above
process. Make sure to test for shorts after each phase.
 You'll notice the stator becomes crowded very quickly. You can clear some room with
a dull object such as a credit card.
 Don’t forget to tag other winding start and end points.

8. Fig. Rewinding in final Stage
Connecting windings
 Now we have 6 wire ends tagged S1,E1,S2,E2,S3,and E3.
 Connect E3 S1, E1 S2 and E2 S3.
 Now we have 3 end which are motor terminals A,B,C
Wire insulation & Bullet connector
 Add wire insulation to copper wire. Here I used insulation sleeve of
Multicore wire to insulate them as shown in picture.
 Add bullet connector to motor terminals as shown in picture.
 Add heat shrink tube coating for extra strength and insulation.
 Done our motor is ready.

9. Fig. Added insulation to motor
Fig. Added Bullet Connector to Motor